1. Field of the Invention
The present invention relates to a recording tape cartridge which accommodates, in a case, a single reel onto which recording tape such as a magnetic tape or the like is wound, principally for use as a recording/replaying medium for computers and the like.
2. Description of the Related Art
Conventionally, a recording tape cartridge (magnetic tape cartridge) at which a magnetic tape, which serves as a recording tape to be used as a data recording/replaying medium for computers or the like, is wound onto a single reel and this reel is accommodated in a case produced of synthetic resin has been well known. At a distal end (a free end) of such a magnetic tape, a leader member, such as a leader pin, a leader tape, a leader block or the like is fixed. A drawing-out mechanism, which is provided at a drive device, draws the leader member out through an opening aperture of the recording tape cartridge and winds the magnetic tape, which is fixed to the leader member, onto a winding reel of the drive device.
A circular opening is formed through a lower face of the recording tape cartridge. A reel gear is provided in an annular form at a lower face center of the reel and exposed through this opening. A drive gear, which is provided at a rotation shaft of the drive device, meshes with the reel gear. With this structure, the reel is driven to rotate. Hence, when the reel of the recording tape cartridge and the winding reel of the drive device are rotated at the same time, data can be recorded to the magnetic tape and/or data that has been recorded to the magnetic tape can be replayed.
At a recording tape cartridge with such a structure, the leader member is a coupling member which is coupled with the drive device side winding reel in a state in which the magnetic tape is pulled tight. However, positions of the opening aperture formed in the case and types of a door which opens and closes the opening aperture and so forth differ for the different types of leader member. For example, in a case with a leader block, the opening aperture is formed at a corner portion at a side in a direction of loading of the recording tape cartridge (the case) into a drive device, and the leader block is anchored so as to close off the opening aperture. That is, the leader block is structured so as to also serve as a door for closing the opening aperture.
This sort of leader block is structured by a stiff body. Therefore, in comparison to a tape-form leader tape, an operation of engagement with the drive device side drawing-out mechanism can be performed more easily, which is advantageous in that abrasion and damage to an engaging portion of the drawing-out mechanism is less likely to occur. Furthermore, when the opening aperture is at the corner portion of the case, this is advantageous in that an angle of drawing-out of the leader block can be freely selected in design of a drive device. For example, design is possible so as to draw out the leader block along a shortest distance to the winding reel, and design is possible so as to complete the operation of drawing-out of the magnetic tape in a short time.
However, if a leader block is anchored at a corner portion of a recording tape cartridge (a case) at times of non-use (when the recording tape cartridge is not loaded at a drive device), there is a problem in that if the corner portion is subjected to an impact, due to dropping or the like, it is likely that the case will be warpingly deformed and that the leader block will fall out from the corner portion.
When the leader block is detached and thrown out from the case due to dropping or the like, a user will consequently be subjected to concern as to whether the functionality of the recording tape cartridge has been affected, and will be subjected to concern as to whether or not the recording tape cartridge will operate in the drive device if repaired by hand. Moreover, in practice, creases may be formed in the magnetic tape when the recording tape cartridge is dropped and the leader block detaches from the case. Furthermore, when the leader block undesiredly detaches, because the leader block itself functions as a door, there is a problem in that dustproofing of the recording tape cartridge is breached.
Accordingly, it has conventionally been thought that impacts due to dropping and the like can be mitigated and effects on the leader block kept to a minimum by, for example, forming the corner portion in a form which is itself easily deformed by warping. However, such structures by themselves have been insufficient as countermeasures for preventing detachment of leader blocks.
Accordingly, as shown in FIG. 8, for example, formation of an aperture 78 in a peripheral wall 74 at a side of a recording tape cartridge 70 (a case 72) in a direction of loading into a drive device, at a position apart from a corner portion 76, and engagement of a leader block 80 with the peripheral wall 74 so as to close up the aperture 78 has been considered (see, for example, Japanese Patent Application Laid-Open (JP-A) No. 2002-298541). According to such a structure, if an impact is applied to this corner portion 76 by dropping or the like and the case 72 is warpingly deformed, the leader block 80 is unlikely to disengage from the aperture 78, because the aperture 78 is provided at a position which is separated from the corner portion 76.
However, because the leader block 80 illustrated in FIG. 8 engages with the peripheral wall 74 when closing off the aperture 78 so as to be coplanar with the peripheral wall 74 and so as to structure a portion of the peripheral wall 74, it is necessary to form the size of the aperture 78 so as to match the size of the leader block 80. Moreover, at times of non-use, because the leader block 80 is continuously in a state of being exposed to the outside, there is a problem in that the leader block 80 is susceptible to scratching and the like. Because, as mentioned above, the leader block 80 is a coupling member which couples at the drive device side winding reel, it is not preferable for dimensional accuracy of the leader block 80 to be altered by damage or the like.
Furthermore, at times of non-use, the reel is urged downward by a coil spring. Consequently, a height position of the reel may differ (become lower) relative to a height position of the leader block. Thus, the magnetic tape may get into a state which extends from the reel to the leader block at an angle in side view. If this condition arises, different tensions will be applied at upper and lower side end portions (below referred to as “edges”) of the magnetic tape. Consequently, problems such as the magnetic tape twisting and the magnetic tape become creased may occur, in addition to which one of these edges may contact and rub against an upper flange of the reel, leading to the occurrence of problems with the magnetic tape being damaged.